This invention relates to plug assemblies and interconnection systems for use with dynamoelectric machines, and more particularly to a plug assembly and interconnection system for an electric motor starting switch and the like.
Typically, capacitors start and split phase induction motors have a run winding and a starting or auxiliary winding. The starting winding is energized during startup of the motor (or when the speed of the motor falls below a specified operating speed) so as to create a rotating field in the stator and to provide sufficient torque to the rotor for starting purposes. However, once the motor has accelerated to a desired operating speed, the starting winding is no longer needed. As is conventional, a switch, referred to as a motor starting switch, is provided in the motor for energizing the starting winding only during startup of the motor and for deenergizing the starting winding once the motor has obtained its desired operating speed. These motor starting switches are conventionally actuated by centrifugal actuator mounted on and rotatable with the rotor shaft of the motor, the centrifugal actuator being responsive to the speed of the motor for changing the starting switch from its start to its run state in response to the motor attaining a predetermined operating speed.
In many applications, in addition to the switch which controls the starting winding, it is desirable to have one or more sets of auxiliary contacts to provide control signals or the like for the particular apparatus such as a washing machine or the like which incorporates the motor. Preferably, these control signals should occur simultaneously with the switching in or out of the starting winding. These auxiliary contacts are normally placed in a single housing with the starting switch. These auxiliary contacts or terminals form a plug assembly wnich can be connected to a plug from the apparatus itself for making electrical connection between the auxiliary terminals and the apparatus. It is desirable that the plug from the apparatus be easily inserted into the starting switch plug assembly and easily removed therefrom for purposes of servicing the apparatus and for assembly. However, because of the severe vibrations which occur in certain applications such as washing machines, it is necessary to provide some sort of latching mechanism between the apparatus plug and the starting switch plug assembly. Heretofore, such plug assemblies have been relatively easy to damage and not altogether satisfactory. For example, it would be desirable for latches used with such assemblies to have a positive latching feel and/or sound. In addition, such latches should keep the two plugs connected even when the wiring harnesss attached to the apparatus plug is jerked. Furthermore, such a latching mechanism should not interfere with the easy insertion of the apparatus plug into the starting switch plug assembly. Moreover, the terminals in prior starting switch plug assemblies may be bent and shorted if the apparatus plug is not inserted correctly.